also know as unlimited-source diffusion; also as predeposition; concentration of diffusant (dopant) on the surface of the wafer remains constant during the diffusion process, i.e. while some dopant atoms diffuse into the substrate additional dopant atoms are continuously supplied to the surface of the wafer.

predeposition

semiconductor doping by diffusion; process of thermal oxidation of silicon in the ambient containing dopant atoms; heavily doped oxide formed is acting as a source of dopant during the diffusion.

limited-source diffusion

also known as drive-in; concentration of diffusant (dopant) on the surface decreases during the diffusion process, i.e. while some dopant atoms diffuse into the substrate no new dopant atoms are supplied to the surface of the wafer.